Devices for forming coils which are inserted into slots of a rotor or stator are described in U.S. Pat. No. 4,106,189, the Japanese patent 54-43 161, and Japanese patent application publication 62-48 240. These patents disclose devices which serve to force the inserted coils radially outward in specific slots of a stator or rotor plate pack in order to allow further layers of coils, or coils of an auxiliary phase, to be inserted. Additionally, insulation strips can be inserted into the slot. This process is referred to as free forming or intermediate forming.
The previously known devices for forming coils in stator or rotor slots have the deficiency of only being suitable for a very specific winding pattern of a specific stator or rotor with radially inwardly open slots. However, four-pole and two-pole motors, for example, are often manufactured which have the same plate section for the stator. In such cases, it is necessary to provide a special forming device even if the dimensions of the stator plate pack are the same for each type of motor, i.e., one forming device for each winding pattern is necessary. The basic difference between the various forming devices is simply that laminae are extended radially with a different distribution around the periphery in order to displace the coil strands outwardly, i.e., to form the coil strands in the slots allocated to the laminae. In this process, the goal is to have the laminae undergo a very specific movement up to a predetermined final position. This will not occur if all laminae are advanced radially with even pressure in accordance with U.S. Pat. No. 4,106,189, because the laminae can reach different final positions depending on the randomly varying positions of the coil wires in the slots.